The management systems of telecommunications networks in accordance with the newest standards, such as SDH (Synchronous Digital Hierarchy) networks, have been defined in international standards, in order that network elements by different manufacturers, located in the same network, may be easily managed through the same network management workstations, or network management products by different manufacturers may be used to manage any network. Generic models for different types of equipment are stored in the management system, and thus equipment by different manufacturers can be managed from the same system if said equipment is in accordance with the generic model.
On the other hand, the management of network elements representing older-generation systems (also new equipment) is more problematic, since there are far more manufacturer-related and equipment-specific variations in the management interfaces. For this reason, specific commercial management products are not available either.
FIG. 1 illustrates the principle on which for example the Applicant's PDH (Plesiochronous Digital Hierarchy) equipment is presently managed. A workstation WS1 of the network management system or a service man's portable workstation WS2 includes software with e.g. a graphical user interface having a Q1 interface and an electrical connection in accordance with ITU-T recommendation V.11 through which data can be transferred asynchronously at rates 75 . . . 19200 bit/s.
Q1 is a master-slave management protocol that is used for the management of the Applicant's PDH network elements. The network elements NE to be managed are coupled on a common management bus MB. The management workstation (WS1 or WS2) is connected either directly to the local management interface of the managed network element or to a desired network element through the management interface of another network element and a management bus of the telecommunications network. The management workstation serves as a master that sends commands to the network element. The network element (slave) does not send anything on its own accord, but only responds to queries sent by the management workstation. The exchange of information between the management workstation and the network element takes place asynchronously in 11-bit frames. Longer messages are divided into several successive frames. A message to be sent may comprise 1 . . . 26 frames. Each message sent by the master element starts with an address frame containing the address of the network element for which the message is intended. Each message sent by the network element again starts with an address frame containing the address of that network element.
As will yet be stated hereinbelow, the management protocol used by the network elements may vary. Nevertheless, the Q1 protocol employed for managing conventional PDH equipment will be used as an example in the following.
In the Q1 protocol, network element management is based on character-based menus. The network elements have a generic main menu for the management thereof; the menu is the same for all Q1-managed equipment. When one alternative is selected from the main menu, the managed network element sends as a response to the management workstation a data structure determining the menu structure that said network element uses under said alternative. FIG. 2 illustrates such a procedure. All network elements may for example have a main menu M1 as shown in the figure, and when it is desired e.g. to look up statistics for a given network element, said network element can return to the management workstation a submenu M2 as shown in the figure, for instance, wherefrom the user can further select the desired alternative. Hence, navigation in the menu tree of the network element takes place in such a way that the user selects from the menu the desired item, information on the selection is forwarded to the network element, which returns in response a new menu wherefrom the user can again select the desired alternative, etc.
Depending for example on the type of the network elements or the version of a given type, there may be differences in the menus used by the network elements. Thus, the management software must be altered according to the manufacturer, type and version of the network element. The menu to be used also varies according to the language used by the network element. The problem with the known management procedure is therefore that it is difficult to maintain the management software at the management workstations, as changes to the management software must be made at numerous management workstations depending on what the managed network element is like.